Beginning approximately 4-6 weeks after completion of arsenic trioxide, patients receive idarubicin IV daily on days 1-3 or 1-4 and filgrastim (G-CSF) subcutaneously daily beginning on day 5 or 6 and continuing until blood counts recover. Treatment repeats every 4 weeks for patients who remain RT-PCR positive or are newly converted to RT-PCR negative (molecular complete remission) following a prior course of idarubicin for a maximum of 3 courses. Patients who remain RT-PCR positive following course 3 of idarubicin receive no further treatment on study.